Printed circuit boards (PCB) and embedded software have become common place in consumer and commercial products. As use of PCBs and embedded software has increased, so has the use of electronic modules. An electronic module (ECU) is a circuit on a PCB that performs a specific function. The ECU may use embedded software to perform complex functions. In modern automobiles, electronic modules perform a variety of functions, and control a wide variety of devices. In automobiles, electronic modules control the radio, brakes, overhead lighting, cruise control, wipers, etc. Outside of automobiles, electronic modules can control any electronic device, from streetlights to cameras, from televisions to telephones.
Design engineers test systems of electronic modules to verify a new system's functionality. The engineers design and build test benches containing all of the electronic modules within the new system. An example of a system may be an entire electronic system in an automobile or an airplane. The testing of a system is done early in the design process, and therefore the actual, production-intent wiring harnesses are not available to interconnect the ECUs. Since the design engineers need to test the system functionality before the final electrical harnesses are created, they need to manually design and build a custom harness. After the engineer designs a new custom harness, a circuit map is created that indicates where the electrical signals from the ECUs should connect. The circuit map may involve the use of a spreadsheet program, such as Microsoft Excel from Microsoft, Inc. of Redmond, Wash.
To ensure that the new system, and therefore the ECUs, function as designed, the ECUs are tested. Electronic module simulators are known to those of ordinary skill in the art. The simulators simulate the sensor inputs to ECUs, such that the ECU software operates as though in the real environment. For example, instead of having a real engine present, the simulator simulates a real operating engine. As a result the ECU's software “thinks” it's connected to a real engine. It is also known that a system may comprise the use of multiple ECUs, each of which must be tested, alone and in concert with the other ECUs that comprise the new system.
As electronic modules have grown in popularity, they have also grown in complexity. Complexity may be measured, at least in part, by the number of pins inserted into the board, by the number of boards required for the electronic module, and by the amount of embedded software within each electronic module. Furthermore, while the actual testing of the electronic system is a complex process, preparing the new system for testing has been a comparatively time consuming, and error-prone process.
In order to test the new electronic system, it is necessary to ensure that current flows and all the software functions as desired by the engineer. This assurance is provided by connecting the ECUs to ECU Simulators and by interconnecting the ECUs to each other. The interconnections represent the future interconnections in the new system. Each ECU pin is connected to a wire that is connected to a specific input of the simulators or other ECUs. This laborious process is fraught with the potential for error. Each pin is manually connected using a wire. While this process may be relatively efficient for 5 or 6 pins, when 500 or 600 pins are connected, the efficiency is degraded. When 3000 or 4000 pins are interconnected, efficiency is nearly lost. Furthermore, although complete accuracy is needed to ensure an accurate test, accuracy is quite difficult to obtain through a maze of 3000 wires.
FIG. 1 illustrates a prior art testing system bench 100. System Bench 100 comprises terminal strips 105 in electric communication with ECUs 130 and simulators 140 via wires 120. Wires 120 are individually connected to a particular pin on terminal strips 105. Between the individual pins on the terminal strips, the engineers manually wire all the interconnections between each module 130 and each simulator 140. The manual wiring is done to represent the same interconnections on the future vehicle the system bench 100 represents. Those of ordinary skill in the art are well aware that the use of terminal strips 105 is optional and often the engineers directly wire the interconnects between ECUs 130 and simulators 140. Although FIG. 1 is shown with 9 total ECUs 130 and simulators 140, those of ordinary skill in the art are well aware that systems with as few as one ECU are possible, with only practical limits for an upper bound for the number of ECUs 130 and simulators 140. The complexity of the system bench 100 correlates directly, and in some systems exponentially, with the number of ECUs 130 and simulators 140, and therefore the number of wires 120.
What is needed therefore, is an improved apparatus and method for testing electronic modules that overcomes these, and other, limitations.